/Engine/Source/Runtime/UMG/Public/Blueprint/WidgetLayoutLibrary.h
Gets the slot object on the child widget as a Size Box Slot, allowing you to manipulate its information.
static [USizeBoxSlot](API\Runtime\UMG\Components\USizeBoxSlot) * SlotAsSizeBoxSlot ( [UWidget](API\Runtime\UMG\Components\UWidget) * Widget )